// 为什么题目里有 30 元
const RMB: [u32; 8] = [100, 50, 30, 20, 10, 5, 2, 1];

pub fn dp_rec_mc(amount: u32) -> u32 {
    let mut amount = amount;
    let mut num = 0;
    while amount != 0 {
        for &cash in &RMB {
            if cash <= amount {
                num += 1;
                amount -= cash;
                break;
            }
        }
    }
    num
}
